As one of light detection devices, a light detection device is known that uses an avalanche photodiode array. This light detection device has a feature capable of detecting light at a single photon level. The light detection device has a problem in that multiplication factors of the avalanche photodiodes vary with a substrate temperature and an ambient temperature. To avoid such a problem, it is known to change reverse voltages applied to the avalanche photodiodes in accordance with a temperature.
For changing the reverse voltages applied to the avalanche photodiodes in accordance with a temperature, a temperature sensor, a temperature sensor driving circuit, and a bias voltage change circuit, and the like are required, thereby having a problem in that the structure is complicated.